Knockdown carpenter&#39;s square.



P. B. HAEDSOCG.

KNOCKDOWN GABPENTERS SQUARE.

APPLIoA'rIoN FILED Ammo, 1912.

Patented June 30, 1914,

v/l/IIIIII IIIIII IA PLANooRAPH co..wAsmNuToN. D.

FRED B. HARDSOCG, 0F OTTUMWA, IGWA.

KNOCKDOWN CARPENTERS SQUARE.

Specification of Letters Patent.

Patent-ed J une 30, 1914.

Application filed April 20, 1912. Serial No. 692,003.

To all whom it may conce/m Be it known that I, FRED B. HARnsoco,

a citizen of the United States, residing at Ottumwa, in the county of Wapello and State of Iowa, have invented certain new and useful Improvements in Knockdown Carpenters Squares, of which the following is a specification.

rThis invention relates to a knock-down carpenters square of that form in which the tongue and blade constitutes separate members, each of which is practically a straight bar of metal.

The invention has particular reference to the means whereby the tongue and blade are secured together.

The main object is to provide a securing means of such form that the connection is established by expanding or enlarging a portion of one of the members which portion seats within a suitably-shaped pocket or groove of the other member. By the use of such construction, a firm connection can be established notwithstanding that the members may wear slightly in use. This is because the member having the expansible portion may be enlarged each time until firmly gripped into the pocket or receving portion of the other member.

Other objects and uses will appear from a detailed description of the invention which consists in the features of construction and combination of parts hereinafter described and claimed.

In the drawings, Figure 1 shows a face view of a corner of the square embodying the features of my invention, the two members being joined together; Fig. 2 shows a face View of the locking end of the tongue; Fig. 3 shows a face view of the locking end of the blade; Fig. 4: shows a cross section taken on the line 1 4 of Fig. 1, looking in the direction of the arrows; Fig. 5 shows a view in end elevation looking in the direction of the arrow 5 of Fig. 1; and Fig. 6 shows a view in end elevation similar to that of Fig. 5, except that the blade has been unlocked and loosened up sufficiently to permit it to be withdrawn from the tongue.

For purposes of convenience, I shall designate one of the members as the tongue and the other one as the blade. It will be seen, however, that the terminology might be reversed, that element having the expansible portion then being called the tongue, and vice versa.

The numeral 7 designates the tongue and the numeral 8 designates the blade in each of the several figures. One of these members-in the construction shown, the

tongue-is provided with a transverse chanl nel or groove 9 adapted to the reception of the end portion of the other member. The end of the blade is split along the line 11, so that when the two portions 12 and 13 are collapsed toward each other, as shown in Fig. 8, their edges 14 and 15 can be easily slipped between the edges 16 and 17 of the channel of the tongue. Means are provided for thereafter forcing the portions 12 and 13 apart and until their edges are firmly gripped against the edges of the channel.

In the particular construction illustrated, the means for forcing the portions 12 and 13 apart, or for expanding the blade takes the form of a member 18 seated between these portions and adapted to expand them when rotated from the position of Fig. 3 into that of Fig. 1. For this purpose, notches 19 and 20 are oppositely formed in the two portions 12 and 13 so that rotation of the member 18 will force these portions apart. The notches 19 and 20 should preferably constitute portions of an elliptical hole. A key or other device may be inserted into a hole 21 of the member 18 for rotating it. The upper and lower faces of the member 18 may be flanged out, as is clearly shown in Fig. 4, so that the said member cannot be removed from the blade although it is free to rotate, as above described. Furthermore, a circular hole 23 may be provided in the tongue at a point immediately beneath the hole 21 of the member 18, so that when the key is inserted into the said hole it can project through the tongue. In order to facilitate the expansion of the members 12 and 13, as above described, the slot 11 terminates in an enlargement 23. In this way, a more elastic construction is provided and danger of cracking or splitting the blade is greatly reduced.

It would be possible to secure a suiicient grip between the tongue and blade simply by the expanding force exerted by the member 18 on the end portions of the blade. However, in order to still further improve the connection, I undercut the sides 16 and 17 of the groove or channel, and furthermore I taper the channel from end to end as is well shown in Figs. 1 and 2. When this is'done, it is not necessary to expand the portions 12 and 18 of the blade with as much force as would otherwise be required to secure a firm connection between the members.

.I do not limit myself to the features of construction herein shown and described, eX- cept as called for in the claim, but I include within the scope of my invention any construction Whereby the tongue and blade of a carpenter-s square may be joined together by expanding a portion of one element into a suitably formed pocket or groove in the other element.

As before stated, it is obvious that the terminology herein used might be reversed, and the portion having the channel 9 might be designated the blade, while the member 'having the expansible portion adapted to Acombination with a blade having a tapered channel formed m one of its faces, the side e walls of said channel being undercut, of a tongue having its end portion split in the direction of its length, the edges of said end portion being beveled to engage the undercutl side Walls of the channel, said end portion of the tongue being entered into the channel of the blade to bring the extreme end of the tongue into the broad portion of the channel, a shoulder on the tongue adapted to contact the edge of the blade for the purpose of accurately positioning the tongue with respect to the blade, and an elliptical locking member rotatably mounted Within the split portion of the tongue and adapted to force apart the two halves of the split portion of the tongue, whereby when said elliptical locking member is rotated for locking purposes the two portions of the split end of the tongue are forced apart to there` by bring their beveled edges into solid engagement with the undercut edges of the vchannel to lock the blade with respect to the tongue, and to maintain the shoulder of the blade in lirm contact with the edge of the tongue, substantially as and for the purpose set forth.

FRED B. HARDSOCG.

lVitnesses:

W. H. KEA'riNG, HARRY E. THORNE.

Copies of this patent may be obtained for ve centseach, by addressing the Commissioner of Patents, Washington, 2D. C. 

